[US P]

Sometimes I am experiencing sudden, - without any pre-warning sign, - extremely sharp, painful pain in my leg. It comes like lighting and goes away the same way. The areas are around behind my knee or near but always at the back of my leg. The pain goes away like never been there. It lasts a few seconds only. The pain is such that in case I would drive, it would loose control of the car. I collapsed on the street several times and screamed uncontrollably. I did go to the emergency room at the first time. They could not find anything! The same goes for my family physician. I am paying over a thousand dollars monthly for health insurance but not sure why. Again, I need to emphasize the all of sudden start of this horrifying pain and the end the same way. I would be grateful for any help!!!!